Recent trends indicate fewer young people are attempting drug use. However, the spectrum of adolescent drug abusers has widened, requiring appropriate treatment models that address their multidimensional needs. The major objective of this proposal is to evaluate the effectiveness of the therapeutic community (TC) approach for treating adolescent substance abusers. A prospective longitudinal design will follow adolescent (13-21 yrs.) admissions (N greater than 500) to 4 modalities in the Phoenix House system which has adapted the TC model in two nonresidential settings in New York City, a residential TC in Orange County, California and the main modality, a residential TC high school in Westchester County, New York. A sample of non admissions (N=50) will also be followed. Social and psychological status will be assessed at entry, 3 points during treatment and at 12 months post treatment. The specific aims of this 5 year study are (1) to describe the social and psychological profiles of adolescents in the 4 modalities to refine the diagnostic match between client status at followup to clarify the link between treatment experience and outcome, (3) and to identify the client, treatment and non treatment factors that contribute to retention and stability of outcomes. The proposed research constitutes the most comprehensive investigation to date of adolescent substance abusers in a single treatment system guided by an explicit perspective and model (the TC) adapted for residential and nonresidential settings. In particular, it will document the effectiveness of an innovative adaptation of the TC as a 24 hour residential high school, the success of which contains significant implications for both the drug treatment and the educational systems.